Of course, without the real book to compare against this "leaked" version, there's no way to be 100% certain its the real thing. But it certainly looks authentic enough. And, if someone has gone to that much trouble to fake it, then Harry Potter fans are even more fanatical than I thought.

It's unclear how the book could have got out, especially given all the tightened security. But, when something is so keenly anticipated, it's hardly surprising that someone grabbed a copy and posted it online.

Ironically, however, I very much doubt the leak will harm sales of the book. As Bruce Schneier notes on his blog, the kind of person who'd bother to download these PDF images will no doubt go out and buy several copies of the hardback as well.